Previous spectrometers have required moving parts to obtain the dispersion of light into its constituent wavelength components. Such moving parts include scanning a diffraction grating to move the dispersed light across the entrance slit of a spectrometer or oscillating a mirror to produce the changing interference patterns for a interferometer. Moving parts have an obvious disadvantage in imposing substantial mechanical complexity into the spectrometer. In some sense the spectral resolution of the spectrometer is always limited by the mechanical precision of its construction and by the mechanical precision of its maintenance. Such mechanical constraints also necessarily limit the mechanical rigidity, stability and transportability of the spectrometer.
Conventional sample analysis using a spectrometer has also been limited to sampling a single area of a specimen plane at a time. This is unfortunate in that many spectroscopic analyses require taking the spectrum of multiple adjacent areas on a specimen. Constructing a matrix of the spectra of an entire sample area is therefore a complex, time consuming operation that is rarely performed.
It is an objective of the present invention to use electrical components to perform all deflections of a beam of light that are needed to obtain a spectrum. It is another objective of the present invention to produce multiple spectra of a sample area using optoelectronic components. It is another objective of the present invention to facilitate making both the dispersive and interferometric measurements of the spectral constituents of light using electrical components.
The present invention achieves these and other objectives using a multisource infrared spectrometer having a source of broad band infrared energy, a relay mirror that focuses the infrared energy at an intercepting mirror, a first object mirror that collimates the infrared energy from the intercepting mirror, a spatial light modulator that receives the collimated infrared energy and reflects it back to the first object mirror, the spatial light modulator including deformable mirror elements, and a controller that deforms the mirror elements according to a predetermined pattern.